This invention generally relates to rotor assemblies, and more particularly to securing rotor blades within and removing rotor blades from rotor assemblies.
In many rotor assemblies, as is well known in the art, a plurality of blades are secured to a rotor disc by axially sliding the blade roots into complementary slots or grooves formed in the disc. Because of this axial or side entry feature, blades of this type are commonly referred to as side entry blades. Once located within the rotor disc, the blades are then secured to the disc against axial movement, effectively locking the blades to the disc. To remove a blade, for example to repair or to replace the blade, the blade is first unlocked from the rotor disc to allow axial movement of the blade root, and then the root is slid out of the disc groove, freeing the blade from the disc.
Prior art blade locking arrangements employed with rotor assemblies of the general type described above often involve considerable time or expense. For example, in many cases, the blade root structure is peened over the rotor disc slot. This, however, requires significant amounts of hand working and thus is costly and time consuming. Moreover, removal of the peened blade structure from the rotor disc may be difficult, entailing substantial time and effort. In other cases, the blades are secured to the rotor disc by a plurality of locking pins, with each pin preventing axial movement of a selected blade and the pin itself held in place by an adjacent blade. With such an interrelated blade locking arrangement, often a plurality of blades must be removed from the rotor assembly in order to remove any one particular blade.
With other arrangements employing locking pins, a worker must have access to and manipulate in some manner both ends of the locking pin. Providing this access may compromise other design considerations; and, where the access is provided, the necessary manipulation may require skilled labor and be relatively time consuming. In still other cases, the locking pin has an atypical shape or design and must be specially manufactured just for one, specific type of rotor assembly.